Arent a lot of the thrown HEAT AT grenades useing top attack with something similar to a parachutes to ensure the orientation of the HEAT is actually aimed at the target and not god knows where?
This does not sound very easy to use on moving targets as not only you need to predict the position of the tank but also give the nad time to properly orient itself downwards before interception.
Not sure if people found a way to make othere thrown HEAT grenades somewhat reliable to be facing the right way upon impact but if not then the HEAT grenades might not offer much range or the grenade might tumble to much in the air and project the penetrator in the wrong direction making it useless.